AD 2016-04-06

[Federal Register Volume 81, Number 38 (Friday, February 26, 2016)]
[Rules and Regulations]
[Pages 9756-9761]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2016-03459]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-0681; Directorate Identifier 2014-NM-201-AD; 
Amendment 39-18400; AD 2016-04-06]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for all The 
Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER 
series airplanes. This AD was prompted by a determination that a 
repetitive test is needed to inspect the components on airplanes 
equipped with a certain air distribution system configuration. This AD 
requires doing repetitive testing for correct operation of the 
equipment cooling system and low pressure environmental control system, 
and corrective actions if necessary. This AD also requires, for certain 
airplanes, installing new relays and doing wiring changes to the 
environmental control system. We are issuing this AD to detect and 
correct latent failures of the equipment cooling system and low 
pressure environmental control system, which, in combination with a 
cargo fire event, could result in smoke in the flight deck and/or main 
cabin, and possible loss of aircraft control.

DATES: This AD is effective April 1, 2016.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of April 1, 
2016.

ADDRESSES: For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone 206-544-
5000, extension 1; fax 206-766-5680; Internet <a href="https://www.myboeingfleet.com">https://www.myboeingfleet.com</a>. You may view this referenced service information 
at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., 
Renton, WA. For information on the availability of this material at the 
FAA, call 425-227-1221. It is also available on the Internet at <a href="http://www.regulations.gov">http://www.regulations.gov</a> by searching for and locating Docket No. FAA-2015-
0681.

Examining the AD Docket

    You may examine the AD docket on the Internet at <a href="http://www.regulations.gov">http://www.regulations.gov</a> by searching for and locating Docket No. FAA-2015-
0681; or in person at the Docket Management Facility between 9 a.m. and 
5 p.m., Monday through Friday, except Federal holidays. The AD docket 
contains this AD, the regulatory evaluation, any comments received, and 
other information. The address for the Docket Office (phone: 800-647-
5527) is Docket Management Facility, U.S. Department of Transportation, 
Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 
New Jersey Avenue SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Stanley Chen, Aerospace Engineer, 
Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle 
Aircraft Certification Office (ACO), 1601 Lind Avenue SW., Renton, WA 
98057-3356; phone: 425-917-6585; fax: 425-917-6590; email: 
<a href="/cdn-cgi/l/email-protection#ea999e8b84868f93c489828f84aa8c8b8bc48d859c"><span class="__cf_email__" data-cfemail="512225303f3d34287f3239343f113730307f363e27">[email&#160;protected]</span></a>.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 by adding an AD that would apply to all The Boeing Company 
Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. 
The NPRM published in the Federal Register on April 1, 2015 (80 FR 
17368) (``the NPRM''). The NPRM was prompted by a determination that a 
repetitive test is needed to inspect the components on airplanes 
equipped with a certain air distribution system configuration. The NPRM 
proposed to require repetitive testing for correct operation of the 
equipment cooling system and low pressure environmental control system, 
and corrective actions if necessary. The

[[Page 9757]]

NPRM also proposed to require, for certain airplanes, installing new 
relays and doing wiring changes to the environmental control system. We 
are issuing this AD to detect and correct latent failures of the 
equipment cooling system and low pressure environmental control system, 
which, in combination with a cargo fire event, could result in smoke in 
the flight deck and/or main cabin, and possible loss of aircraft 
control.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the NPRM and 
the FAA's response to each comment.

Request To Clarify Conditions Leading to Unsafe Condition

    Boeing requested that we revise the unsafe condition to clarify 
that latent failures of the equipment cooling system and low pressure 
environmental control system alone do not create the unsafe condition 
addressed in the NPRM. Boeing explained that the unsafe condition is a 
combination of a failure of both systems along with a cargo fire event, 
which could lead to a smoke penetration hazard.
    We agree to revise the description of the events leading to the 
unsafe condition, and have revised the SUMMARY section in this final 
rule and paragraph (e) of this AD accordingly.

Request To Clarify Unsafe Condition

    Boeing requested that we revise the NPRM to clarify that the hazard 
being mitigated by the NPRM is smoke penetration into the occupied 
areas of the airplane--the flight deck or the main cabin (not just the 
flight deck). Boeing stated that failure of the equipment cooling 
system and/or low pressure environmental control system, in combination 
with a cargo fire event, could lead to cargo smoke penetration into the 
flight deck and/or main cabin, either of which could be catastrophic.
    We agree that clarification is needed to specify that the hazard 
being mitigated by the NPRM is smoke penetration into flight deck and 
main cabin, which are occupied areas of the airplane. We have revised 
the SUMMARY section in this final rule and paragraph (e) of this AD 
accordingly.

Request To Match Repetitive Interval in Service Information

    Boeing, Delta Airlines (Delta), United Airlines (United), and Yuta 
Kobayashi requested that we revise the repetitive interval for the 
operational test from 9,000 flight cycles to 9,000 flight hours. Boeing 
stated that a 9,000 flight-hour interval is supported by a fault tree 
analysis, whereas the repetitive interval of 9,000 flight cycles 
required by the NPRM is not. Mr. Kobayashi stated that a correction 
needed to be made since Boeing Alert Service Bulletin 737-26A1137, 
dated May 22, 2014, states the repetitive interval in flight hours.
    We agree with the request to revise the repetitive interval since 
the repetitive interval in flight hours matches the interval stated in 
Boeing Alert Service Bulletin 737-26A1137, dated May 22, 2014. In the 
proposed AD, we inadvertently specified flight ``cycles'' instead of 
flight ``hours.'' We have revised the interval in paragraph (g) of this 
AD from flight ``cycles'' to flight ``hours.''

Request To Clarify Airplanes Subject to Repetitive Testing Requirement

    The Discussion section of the NPRM stated that a repetitive test is 
needed on airplanes equipped with an air distribution system that had 
been reconfigured in accordance with Boeing Special Attention Service 
Bulletin 737-26-1122. Boeing requested that we revise the NPRM to 
clarify that all Model 737-600, -700, -700C, -800, -900 and -900ER 
airplanes are subject to the repetitive testing (as specified in Boeing 
Alert Service Bulletin 737-26A1137, dated May 22, 2014)--not just those 
airplanes with reconfigured air distribution systems. Boeing added that 
Model 737-700C and 737-900 airplanes were not subject to the same 
changes and thus were not included in the effectivity of Boeing Special 
Attention Service Bulletin 737-26-1122, Revision 1, dated August 13, 
2009.
    We agree that Boeing Alert Service Bulletin 737-26A1137, dated May 
22, 2014, describes procedures for the operational testing of the 
equipment cooling system and low pressure environmental control 
systems, and that all 737-600, -700, -700C, -800, -900 and -900ER 
airplanes are subject to this repetitive testing. However, the 
Discussion section that appeared in the NPRM is not repeated in this 
final rule. Therefore no change has been made to this final rule in 
this regard.

Request To Exclude Certain Airplanes From Applicability

    Delta requested that we revise the NPRM to exclude airplanes that 
have not been modified by Boeing Special Attention Service Bulletin 
737-26-1122, Revision 1, dated August 13, 2009. Delta further requested 
that these airplanes be subject to evaluation for additional separate 
rulemaking.
    Delta stated that it believes two separate airworthiness concerns 
must be addressed. Delta stated that the first concern identified by 
the NPRM is a potential latent failure of the equipment cooling system 
and low pressure environmental control system; Delta noted this 
condition is addressed by Boeing Alert Service Bulletin 737-26A1137, 
dated May 22, 2014.
    Delta stated that the second concern, not identified by the NPRM, 
is the need to properly isolate the occupied areas of the airplane from 
smoke intrusion in the event of a cargo compartment fire; Delta noted 
this condition is addressed by the following service information:
    <bullet> Boeing Special Attention Service Bulletin 737-26-1121, 
Revision 1, dated October 26, 2009.
    <bullet> Boeing Special Attention Service Bulletin 737-26-1122, 
Revision 1, dated August 13, 2009.
    <bullet> Boeing Special Attention Service Bulletin 737-21-1135, 
Revision 1, dated November 13, 2008.
    <bullet> Boeing Special Attention Service Bulletin 737-21-1163, 
Revision 1, dated December 17, 2009.
    Delta stated this service information introduces, among other 
tasks, better sealing of the cargo compartment and changes to the 
environmental control system to keep the cargo compartment at a lower 
pressure than that of the cabin in order to keep smoke from a cargo 
compartment fire out of occupied areas.
    We disagree with the request to exclude the airplanes identified by 
the commenter and consider separate rulemaking for those airplanes. The 
primary airworthiness concern addressed by the requirements in this AD 
is the lack of a procedure to detect and correct latent failures of the 
equipment cooling system and low pressure environmental control system, 
which, in combination with a cargo fire event, could result in smoke in 
the flight deck and/or main cabin, and possible loss of aircraft 
control. This unsafe condition affects all Model 737-600, -700, -700C, 
-800, -900, and -900ER airplanes, regardless of whether Boeing Special 
Attention Service Bulletin 737-26-1122, Revision 1, dated August 13, 
2009, has been done. Therefore, all Model 737-600, -700, -700C, -800, -
900, and -900ER airplanes are subject to the repetitive testing in 
Boeing Alert Service Bulletin 737-26A1137, dated May 22, 2014, not just 
those airplanes reconfigured using Boeing Special Attention Service 
Bulletin 737-26-1122, Revision 1, dated August 13, 2009.
    For certain airplanes, Boeing Special Attention Service Bulletin 
737-26-

[[Page 9758]]

1122, Revision 1, dated August 13, 2009, is a concurrent requirement 
because the actions specified Boeing Special Attention Service Bulletin 
737-26-1122, Revision 1, dated August 13, 2009, must be done to make 
sure the testing results are satisfactory (e.g., electrical components 
that are required to reconfigure the air distribution system during a 
cargo fire event need to be installed).
    In addition, the installation and changes specified in paragraph B. 
``Concurrent Requirements'' of Boeing Special Attention Service 
Bulletin 737-26-1122, Revision 1, dated August 13, 2009, will need to 
be implemented, if not already done, in order accomplish the concurrent 
requirements as specified in Boeing Special Attention Service Bulletin 
737-26-1122, Revision 1, dated August 13, 2009. These measures are 
necessary to properly isolate the occupied areas of the aircraft from 
smoke penetration in the event of a cargo compartment fire, such as 
changes to the cargo compartment sealing and equipment cooling system 
to keep the cargo compartment at a lower pressure than the cabin 
pressure. Therefore, we have not changed this final rule regarding this 
issue.

Request To Incorporate Additional Service Information and Revise the 
Costs of Compliance Section

    Delta and Southwest Airlines (Southwest) requested that the Costs 
of Compliance section of the NPRM be revised to capture the costs of 
the following service information since they are identified as 
``Concurrent Requirements'' in Boeing Special Attention Service 
Bulletin 737-26-1122, Revision 1, dated August 13, 2009:
    <bullet> Boeing Special Attention Service Bulletin 737-26-1121, 
Revision 1, dated October 26, 2009.
    <bullet> Boeing Special Attention Service Bulletin 737-21-1135, 
Revision 1, dated November 13, 2008.
    <bullet> Boeing Special Attention Service Bulletin 737-21-1163, 
Revision 1, dated December 17, 2009.
    Delta stated these concurrent service bulletins add a significant 
burden to operators in terms of labor and time since they amount to 190 
additional work-hours. Delta added that since these concurrent actions 
add significant change in scope, it is necessary to withdraw the 
existing proposed rule, allow operators the opportunity to comment on 
their incorporation, and reissue a revised rule with a new comment 
period. Additionally, Delta asked that these documents be specified by 
their explicit revision level in order to ensure the correct intended 
compliance actions are satisfied.
    We agree to add the labor and parts costs for concurrent 
accomplishment of Boeing Special Attention Service Bulletin 737-26-
1122, Revision 1, dated August 13, 2009, because it is a requirement of 
this final rule for Group 1 airplanes; the costs for this action were 
inadvertently omitted from the NPRM.
    We also acknowledge the installation and changes specified in 
paragraph B. ``Concurrent Requirements'' of Boeing Special Attention 
Service Bulletin 737-26-1122, Revision 1, dated August 13, 2009, may 
also need to be done for certain airplanes. We have therefore revised 
the Costs of Compliance section of this final rule by adding 208 work-
hours and a parts cost of $27,323 for the concurrent action.
    We do not agree to withdraw the existing NPRM and reissue a revised 
NPRM with a new comment period. To delay this final rule would be 
inappropriate, since we have determined that an unsafe condition 
exists. However, under the provisions of paragraph (j) of this AD, we 
may approve requests for adjustments to the compliance time if data are 
submitted to substantiate that such an adjustment would provide an 
acceptable level of safety. We have not changed this final rule in this 
regard.

Request To Clarify Conflicting Concurrent Requirements

    <a href="http://Jet2.com">Jet2.com</a> requested that compliance guidance be given for airplanes 
equipped with Supplemental Type Certificate (STC) ST02076LA (http://
rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/
73f6dd3b3bfe1890862578af0053cf0a/$FILE/ST02076LA.pdf); specifically, 
<a href="http://Jet2.com">Jet2.com</a> asked for clarification for airplanes that accomplished STC 
ST02076LA as an alternative action to installing the automatic shutoff 
system for the center tank fuel boost pumps using Boeing Alert Service 
Bulletin 737-28A1206, Revision 2, dated May 21, 2009, which is required 
by AD 2011-18-03, Amendment 39-16785 (76 FR 53317, August 26, 2011). 
<a href="http://Jet2.com">Jet2.com</a> explained that while the concurrent service information is 
clear for accomplishing the required actions of the proposed AD, 
actions for airplanes having STC ST02076LA are not clear.
    We agree to clarify the concurrent requirements of this AD. 
Paragraph B., ``Concurrent Requirements,'' of Boeing Special Attention 
Service Bulletin 737-26-1122, Revision 1, dated August 13, 2009, refers 
to Boeing Special Attention Service Bulletin 737-21-1135, dated 
December 12, 2007, for certain changes. However, Boeing Special 
Attention Service Bulletin 737-21-1135, dated December 12, 2007, 
inadvertently specified concurrent accomplishment of Boeing Alert 
Service Bulletin 737-28A1206, dated January 11, 2006. Boeing 
subsequently issued Special Attention Service Bulletin 737-21-1135, 
Revision 1, dated November 13, 2008, which no longer identifies Boeing 
Alert Service Bulletin 737-28A1206, dated January 11, 2006, as 
concurrent service information. We have revised paragraph (h) of this 
AD to clarify the concurrent requirements and state that Boeing Alert 
Service Bulletin 737-28A1206, dated January 11, 2006, is not required 
by this AD.

Request To Clarify Initial Compliance Time for Production Airplanes

    American requested that we clarify the initial compliance times for 
airplanes that have not yet been delivered, since the proposed AD 
specifies a compliance time for the initial testing of only in-service 
airplanes, but not airplanes that are in production. American also 
requested a more definitive method of determining aircraft effectivity 
than relying on ``the `Get Effectivity' function on <a href="http://myboeingfleet.com">myboeingfleet.com</a>'' 
as specified in Boeing Alert Service Bulletin 737-26A1137, dated May 
22, 2014.
    We agree that clarification is necessary. Group 3 airplanes in 
Boeing Alert Service Bulletin 737-26A1137, dated May 22, 2014, are 
identified as those having line numbers 1701 and all line numbers after 
1701. It is not necessary to use the `Get Effectivity' function on 
``<a href="http://myboeingfleet.com">myboeingfleet.com</a>'' because airplanes in production are Group 3 
airplanes. The compliance time for Group 3 airplanes as specified in 
the NPRM is within 10 months. However, we have determined that for 
airplanes having line numbers 4923, 4924, and 4926 and subsequent, 
which were delivered after the issuance of Boeing Alert Service 
Bulletin 737-26A1137, dated May 22, 2014, a compliance time of ``before 
the accumulation of 9,000 total flight hours'' will provide an 
acceptable level of safety. We have coordinated this change with 
Boeing. As a result, we have restructured paragraph (g) to include new 
subparagraphs (g)(1) and (g)(2).

Request To Revise Initial Compliance Time Relative to AD Effective Date

    United requested that we clarify the initial compliance times for 
the test for correct operation of the equipment cooling system and low 
pressure environmental control system of the

[[Page 9759]]

proposed AD. United requested that the compliance time be revised from 
the effective date of the service bulletin to the effective date of the 
AD since Boeing Alert Service Bulletin 737-26A1137, dated May 22, 2014, 
was not required at the time it was published and therefore, some 
operators may already be beyond the compliance time when this AD is 
issued.
    We agree that clarification is necessary. This AD requires 
compliance within the specified compliance time after the effective 
date of this AD. This provision was specified in paragraph (i) of the 
proposed AD, and is retained in this AD. We have not changed this AD in 
this regard.

Request To Refer to a Maintenance Planning Document (MPD) as a Method 
of Compliance

    Aeroflot requested that we refer to Boeing Maintenance Planning 
Document B737 MPD 21-050-00. Aeroflot stated that the MPD and Boeing 
Alert Service Bulletin 737-26A1137, dated May 22, 2014, refer to the 
same task specified in Boeing Airplane Maintenance Manual 21-27-00-700.
    We disagree with the request. Although this final rule does not 
refer to Boeing B737 MPD 21-050-00 as a method of compliance, operators 
may apply for an alternative method of compliance (AMOC) for these 
actions in accordance with the provisions of paragraph (j)(1) of this 
AD if sufficient data are submitted to substantiate that the MPD 
provides an acceptable level of safety. We have not changed this AD in 
this regard.

Clarification Regarding the Installation of Winglets

    Aviation Partners Boeing stated that the installation of winglets 
per Supplemental Type Certificate (STC) ST00830SE (<a href="http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/408E012E008616A7862578880060456C?OpenDocument&Highlight=st00830se">http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/408E012E008616A7862578880060456C?OpenDocument&Highlight=st00830se</a>) does 
not affect compliance.
    We agree with the commenter that Supplemental Type Certificate 
(STC) ST00830SE (<a href="http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/408E012E008616A7862578880060456C?OpenDocument&Highlight=st00830se">http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/408E012E008616A7862578880060456C?OpenDocument&Highlight=st00830se</a>) does 
not affect the accomplishment of the manufacturer's service 
instructions. Therefore, the installation of STC ST00830SE does not 
affect the ability to accomplish the actions required by this AD. We 
have not changed this AD in this regard.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
this AD with the changes described previously and minor editorial 
changes. We have determined that these minor changes:
    <bullet> Are consistent with the intent that was proposed in the 
NPRM for correcting the unsafe condition; and
    <bullet> Do not add any additional burden upon the public than was 
already proposed in the NPRM.
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this AD.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin 737-26A1137, dated May 
22, 2014, which describes procedures for repetitive testing for correct 
operation of the smoke clearance mode of the equipment cooling system 
and low pressure environmental control system, and applicable 
corrective actions.
    We also reviewed Boeing Special Attention Service Bulletin 737-26-
1122, Revision 1, dated August 13, 2009, which describes procedures for 
installing new relays and doing wiring changes to the environmental 
control system.
    This service information is reasonably available because the 
interested parties have access to it through their normal course of 
business or by the means identified in the ADDRESSES section.

Costs of Compliance

    We estimate that this AD affects 1,372 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                  Cost on U.S.
             Action                    Labor cost            Parts cost      Cost per product      operators
----------------------------------------------------------------------------------------------------------------
Operational Test...............  4 work-hours x $85 per  $0...............  $340 per           $466,480 per
                                  hour = $340 per                            operation test     operation test
                                  operation test cycle.                      cycle.             cycle.
Installation of new relays and   Up to 208 work-hours x  Up to $27,323....  Up to $45,003....  Up to
 wiring changes to the            $85 per hour =                                                $27,586,839.
 environmental control system     $17,680.
 (concurrent actions) (up to
 613 airplanes).
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary system fault 
isolation and replacements that would be required based on the results 
of the operational test. We have no way of determining the number of 
aircraft that might need these actions:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Perform system fault isolation and replace     10 work-hours x $85 per hour =               $0             $850
 faulty component.                              $850.
----------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.

[[Page 9760]]

    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

2016-04-06 The Boeing Company: Amendment 39-18400; Docket No. FAA-
2015-0681; Directorate Identifier 2014-NM-201-AD.

(a) Effective Date

    This AD is effective April 1, 2016.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 737-600, -700, -
700C, -800, -900, and -900ER series airplanes, certificated in any 
category.

(d) Subject

    Air Transport Association (ATA) of America Code 2120, Air 
Distribution System.

(e) Unsafe Condition

    This AD was prompted by a determination that repetitive 
inspection is needed to inspect the components on airplanes equipped 
with a certain air distribution system configuration. We are issuing 
this AD to detect and correct latent failures of the equipment 
cooling system and low pressure environmental control system, which, 
in combination with a cargo fire event, could result in smoke in the 
flight deck and/or main cabin, and possible loss of aircraft 
control.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Repetitive Operational Tests and Corrective Action

    At the applicable times specified in paragraph (g)(1) or (g)(2) 
of this AD, do a test for correct operation of the smoke clearance 
mode of the equipment cooling system and low pressure environmental 
control system, and do all applicable corrective actions, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-26A1137, dated May 22, 2014. Do all applicable 
corrective actions before further flight. Repeat the test thereafter 
at intervals not to exceed 9,000 flight hours.
    (1) For airplanes other than those identified in paragraph 
(g)(2) of this AD: At the applicable times identified in paragraph 
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-26A1137, 
dated May 22, 2014, except as required by paragraph (i) of this AD.
    (2) For airplanes having line numbers 4923, 4924, and 4926 and 
subsequent: Before the accumulation of 9,000 total flight hours.

(h) Concurrent Requirements

    For Group 1 airplanes identified in Boeing Alert Service 
Bulletin 737-26A1137, dated May 22, 2014: Before or concurrently 
with accomplishing the initial operational test required of 
paragraph (g) of this AD, install new relays and do wiring changes 
to the environmental control system, in accordance with the 
Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 737-26-1122, Revision 1, dated August 13, 2009. When the 
actions required by this paragraph are done, the installation and 
changes specified in paragraph B. ``Concurrent Requirements'' of 
Boeing Special Attention Service Bulletin 737-26-1122, Revision 1, 
dated August 13, 2009, must also be done. However, operators should 
note that Boeing Alert Service Bulletin 737-28A1206, dated January 
11, 2006, is not required by this AD.

(i) Exception to the Service Information

    Where paragraph 1.E., ``Compliance,'' of Boeing Alert Service 
Bulletin 737-26A1137, dated May 22, 2014, specifies a compliance 
time ``after the original issue date of this service bulletin,'' 
this AD requires compliance within the specified compliance time 
after the effective date of this AD.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested 
using the procedures found in 14 CFR 39.19. In accordance with 14 
CFR 39.19, send your request to your principal inspector or local 
Flight Standards District Office, as appropriate. If sending 
information directly to the manager of the ACO, send it to the 
attention of the person identified in paragraph (k) of this AD. 
Information may be emailed to: <a href="/cdn-cgi/l/email-protection#a39a8ee2edee8ef0c6c2d7d7cfc68ee2e0ec8ee2eeece08ef1c6d2d6c6d0d7d0e3c5c2c28dc4ccd5"><span class="__cf_email__" data-cfemail="80b9adc1cecdadd3e5e1f4f4ece5adc1c3cfadc1cdcfc3add2e5f1f5e5f3f4f3c0e6e1e1aee7eff6">[email&#160;protected]</span></a>.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.
    (3) For service information that contains steps that are labeled 
as Required for Compliance (RC), the provisions of paragraphs 
(j)(3)(i) and (j)(3)(ii) of this AD apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, must be done to comply 
with the AD. An AMOC is required for any deviations to RC steps, 
including substeps and identified figures.
    (ii) Steps not labeled as RC may be deviated from using accepted 
methods in accordance with the operator's maintenance or inspection 
program without obtaining approval of an AMOC, provided the RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.

(k) Related Information

    For more information about this AD, contact Stanley Chen, 
Aerospace Engineer, Cabin Safety and Environmental Systems Branch, 
ANM-150S, FAA, Seattle Aircraft Certification Office (ACO), 1601 
Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-6585; fax: 
425-917-6590; email: <a href="/cdn-cgi/l/email-protection#5c2f283d32303925723f3439321c3a3d3d723b332a"><span class="__cf_email__" data-cfemail="ee9d9a8f80828b97c08d868b80ae888f8fc0898198">[email&#160;protected]</span></a>.

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing Alert Service Bulletin 737-26A1137, dated May 22, 
2014.
    (ii) Boeing Special Attention Service Bulletin 737-26-1122, 
Revision 1, dated August 13, 2009.

[[Page 9761]]

    (3) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P. O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone 206-544-
5000, extension 1; fax 206-766-5680; Internet <a href="https://www.myboeingfleet.com">https://www.myboeingfleet.com</a>.
    (4) You may view this service information at FAA, Transport 
Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For 
information on the availability of this material at the FAA, call 
425-227-1221.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, call 202-741-6030, or go to: <a href="http://www.archives.gov/federal-register/cfr/ibr-locations.html">http://www.archives.gov/federal-register/cfr/ibr-locations.html</a>.

    Issued in Renton, Washington, on February 8, 2016.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-03459 Filed 2-25-16; 8:45 am]
 BILLING CODE 4910-13-P